1. Field of the Invention
The present invention relates to a method for modifying the effective power in one or several power consuming devices disposed in an A/C system in order to provide data transmission capabilities via a power line thereof.
2. Description of Related Art
What can be taken from the present state of art (like the U.S. Pat. No. 5,491,463) are methods to individually control appliances, whereby address-data as well as control-data are fed in the zero-crossings of the supplying power. Hereby the disadvantage is provided, that an additional 120 kHz-Generator is necessary to create particular burst signals and it is also necessary that the receiver has to provide complex detector circuits to enable said feeding in said zero-crossings.
What is also known, for instance derivable from EP 1 134 910, is a method defining different types of bits by changing the duration of zero-crossings or by blanking the supplying voltage herewith enabling it to detect said different types of bits as well as to detect the respective control data for a receiver of said data by help of only a simple circuit.
Using said method it is technically possible supply data to a plurality of power consuming devices which are all connected to said AC-power-supply line, by interrupting said power line in the case of a zero-crossing of the sinus curve of the voltage close to the zero crossing (i.e. “blanking”). Due to said concept, none of the power consuming devices may comprise and provide any capacitive power-portions, since they would disturb the respective zero-crossing of the supplying voltage-sinus-curve. Consequently said state of art teaches that only power consuming devices can be attached, which show pure ohmic behaviour without any capacitive or inductive portions, which means that they show a phase angle of almost zero, since in any other case the zero-crossing would be overlaid by the reactive current of the respective power consuming device showing capacitive or inductive behaviour.
The methods taught by the state of art provide the same disadvantage which is not to providing any possibility to transfer data as long as electronic devices are connected to said power-line, supposed to transfer said data, providing capacitive or inductive portions of power, like for instance electric motors, kitchen devices, electric tools, fluorescent lamps, electronic devices, like a PC, TV, HiFi-Rack.
Consequently the solutions taught by the state of art are neither appropriate to teach any transfer of data or is only able to teach a transfer of data in a very limited way.